1. Field of the Invention
The present invention relates to a work visual inspection device and a work visual inspection method for performing the visual inspection (appearance inspection) on works (e.g., electronic components) by capturing images of surfaces of the works by using a work imaging modulo while conveying the works. In particular, the present invention relates to a work visual inspection device and a work visual inspection method with which the focal point of the work imaging module can be adjusted with ease even when the shape of the inspection object works (works as the object of inspection) is changed.
2. Description of the Related Art
There has been known a work visual inspection device that performs the visual inspection on works (e.g., electronic components each in a hexahedral shape) by setting the works on the top of a rotating disk-shaped transparent glass table, conveying the works by having them drawn to the top of the glass table by electrically charging the under surface of the glass table with a charging module (e.g., ionizer), and capturing images of surfaces of the works by using a work imaging module (see JP-A-2011-133458).
In such a work visual inspection device, the focal point of the work imaging module has to be adjusted when the shape of the work is changed (e.g., when the inspection object work is changed from a large work to a small work). However, the focal adjustment of the work imaging module requires high-accuracy adjustment work, such as precisely moving a component of the work imaging module along its optical axis.    Patent Document 1:JP-A-2011-133458